The invention refers to a remote controlled submersible drogue forming a probe-carrier, in particular for marine research under water, which is connected by means of a towrope or probe cable to a towing craft and comprises a lifting body which exhibits a longitudinal profile which generates a dynamic lift, a static stabilizer arranged in the lifting body, an adjustable elevator and also a towrope attachment.
In a known drogue of this kind (see U.S. Pat. No. 3,688,730) the towrope attachment is provided by means of a "balance", i.e., the rope is attached by means of a forked stirrup to two hingepins protruding sideways out of the lifting body. This kind of attachment of the towrope, as is both easily demonstrated in theory and also has been proved by practical tests, prevents any self-stabilizing of the transverse axis of the drogue. The stirrup holds the transverse axis of the drogue always perpendicular to the direction of the end of the rope. Even with very perfect symmetrical alignment of the drogue and the stirrup and with oscillation-free straight-ahead running of the drogue a trifling alteration off-course of the towing vessel and hence an alteration of the direction of the rope is enough to tilt the initial desired and achieved horizontal position of the transverse axis of the drogue which runs through the two hingepins, and thereby induce motion of the drogue along an arc of a circle the centre of which lies in the effective direction of the rope, up to the surface of the water. This circular motion, depending upon the length of rope and depth of immersion, leads to surfacing of the drogue sideways from the original path of tow 90.degree., or further listing or to motion of the drogue on a spiral path. Again, the lifting body of the known device exhibits an essentially elliptical cross-section which as regards transverse stabilization with the towed body set at an angle is of equally little advantage, since because of the convex superficial shape of the ellipse and a backwater curve shifting arbitrarily with differing angle of incident flow the pressure ratios on the surface of the lifting body are such that a list is increased rather than its coming to a restoration of the desired aligned position. Finally the stabilizer in the case of the known applicance extends over only part of the length of the lifting body and has the shape of an aerofoil profile.
The static stabilizing effect which is striven for by this is relatively slight when measured against the great technical and structural outlay upon the aerofoil profile. Furthermore the latter prevents simple fitting of any kind of measuring probe or the pressure housing necessary for it, so that for this purpose the lifting body must be employed.
Another known drogue (see West German OS No. 22 07 880) consists of a Zepplin like stream-lined hull, lifting surfaces and a vertical fin which are combined together into one structural unit. At the rear edge of the lifting surfaces combined elevator-ailerons are arranged, whilst in the end region of the vertical fin a rudder is arranged. The towing and supply cable is hinged-on near to the dynamic centre of the hull. This drogue has indeed at adequate speed an adequate degree of floatation stability, but the static stability is inadequate. Also it has no adequate stability against turning, i.e., listing or "spinning". once a certain sideways tilt is reached. By the attachment of the cable near to the dynamic centre of gravity of the drogue the deficient static and dynamic stability is only partially compensated, but free deflectability of the cable is not possible. In order to be able to sink the drogue to greater depths it is necessary to let out a greater length of cable from the towing craft.